Gun type trowel



Sept 3, 1957 H. P. scHoEN 2,804,767

GUN TYPE TROWEL Filed June 2l, 1955 2 Sheets-Sheet l Sept 3, 1957 A H. P. scHoEN 2,804,767

'GUN TYPE: TROWEL l Filed June 21, 1955 2 Sheets-Sheet 2 :Ezr

@Harz/9 P Schoen.

nited States Patent GUN TYPE TROWEL Harvey P. Schoen, Elgin, Ill.

Application June 21, 1955, Serial No. 517,028

2 Claims. (Cl. 72-138) This invention relates to gun type trowels for spreading finishing material such as plaster, mortar, cement and the like on wall surfaces, particularly for finishing the joints of dry wall constructions either flat or cornered.

Heretofore, various difficulties were encountered in work of this kind, mainly when working with trowels attached to the outlet nozzles of plastering machines and the like. The new gun type trowel allows rapid, yet accurate, smooth and long continued finishing of such areas.

The improvement has been achieved by a novel duct structure between the gun and the blade ofthe trowel, distributing the finishing material in suitably predetermined manner before it reaches the blade. A joint can thus be filled and covered with less manual squeezing of the material by the trowel blade, and correspondingly with greater easel and the same, greater accuracy than before.. V Y y The details will be understood more readilyuponv a perusual of theN description of preferred embodiments, which follows.

In the drawing:

Figure 1 is a perspective view of a caulking gun equipped with a trowel according to this invention, particularly for work on at dry wall surfaces.

Figure 2 is a side View of the trowel.

Figure 3 is a section taken along lines 3-3 in Figure 2.

Figure 4 is an enlarged section taken along lines 4 4 in Figure 2.

Figure 5 is a side view of a trowel according to this invention, for work on vertical outside corners.

Figure 6 is a front view of the trowel of Figure 5.

Figure 7 is a top view of the trowel of Figures 5 and 6, taken along lin'es 7-7 in Figure 5; and

Figure 8 is a top View of a trowel according to this invention, for work on vertical inside corners.

Referring first to Figures 1 to 4:

The caulking gun 10 has a conventional feeder, valve or other mechanism .11 for the regulated discharge of the finishing material into the trowel. The new trowel has an intake fitting 12 which is shown as having internal threads 13 whereby it can be connected with the discharge end of the gun. An adaptor 14 in form of a short and suitably trimmed pipe nipple connects the intake member 12 with the interior of the hollow portion 15 of the trowel proper. This hollow portion extends along the front or working side of a resilient trowel blade 16. It discharges adjacent the working edge 17 of said blade, through a series of discharge nozzles 18, a Short distance below said edge; said series of nozzles extending symmetrically over a middle portion of the width of the blade 16 and being shorter than the same.

The discharge openings 18 are advantageously formed by means of a wall member 19 which is generally flat and approximately parallel with the blade 16. This wall 19 is equally resilient as the blade 16, about any axis normal to the edge 17, but is corrugated in directions approximately parallel with the side edges 20, 21 of the to employ such a design in the present case.

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blade. High points of such corrugations are secured to the front surface of the blade, for instance by spot welding or soldering, thereby defining the discharging openings 18 between the walls 19 and 16. The finishing material is guided from the hollow inlet section 15 to the discharge openings 18 by side walls 22 interconnecting the parallel walls 16, 19 and secured thereto as by soldering or welding.

It is usual in the construction of trowel blades to employ a forwardly aring design such as that of a triangle or blunted triangle or trapezium, and it is preferred Accordingly the side walls 22 are also given a forwardly flaring direction. However, it is preferred to backwardly extend their lower portions 23, connecting them with the material-receiving chamber 15, and to make the side and bottom walls 24, 25 of the material-receiving section substantially coincident with the corresponding edges of the trowel. Thus the material-receiving section itself has substantially pentagonal shape as best shown in Figure l, whereby the fiow of the finishing material from the gun 10 is directed into the desired direction parallel with the blade 16 with a minimum of fluid friction and a maximum of uniformity of distribution. The distribution of the flow of the finishing material, over the different orifces 18, is substantially achieved in the narrowed section or throat 26 of the chamber and duct, between the walls 22 and 23, and not as heretofore at the outlet end of the duct itself. At the same time the aforementioned resiliency of the duct and trowel walls,

' about any axis normal to the trowel edge 17, safeguards desirable smoothness of operation, wherein the entire trowel structure and the finishing material guided thereby will follow the surface contoury of the dry wall'being finished, rather than` any arbitrary contour of theltrowel itself. Heretofore the discharge nozzles of gun type trowels interfered with such smooth operation.

In operation, the finishing material is supplied from the gun 10 to the trowel, for instance by the pressure of a preload spring in the gun, not shown, under control of the mechanism 11. The material arrives in the pentagonal chamber 15 and ows therefrom along the front of the blade 16 to the openings 18; each opening receiving a predetermined, for instance equal part of the total material flow due to the effect of the throat or restriction 26, and in spite of slight distances between the different openings 18 from the throat and unavoidable slight distances in orifice areas due to the attachment of the corrugations to the blade.

The gun and trowel may be held at the approximate angle shown in Figures 2 and 4, at the start of operation. When an initial supply of finishing material has been discharged, the angle 27 between the wall 28 and the blade 16 is usually made more acute, incident to which there is also applied some exure of the resilient blade 16, about a horizontal axis. Such flexure is limited to the portion of the blade 16 between the -openings 18 and the edge 17, thereby avoiding interference with the uniformity of material flow upon any change of such flexure and angular direction of the blade. ln earlier gun trowels the plaster had to be Very careful in this respect whereas the operation is greatly simplified by the combined distributing and structural effects of the present flat and corrugated members 16, 19.

Thus the finishing of a joint in a dry wall, or any similar operation, can be performed rapidly, easily and yet very accurately and smoothly and without irregular material accumulations at any point. The operation can be performed in the same manner in spite of slight convexity and/or concavity in a dry wall panel, caused by the nailing thereof of the wall studs, by warpage of the wall under construction 0r similar disturbances, which Patent-eed sept.V 3', 1957l j were a distinct problem in the use of the finishingequipment heretofore known. The new gun trowel is practically independent of such disturbances and problems.

Referring now to Figures 4 to 7:

The invention isV here applied to the finishing ofra corner in ay dry wallan operation wherein the problem of uniform material distribution has been particularly disturbing with the use of equipment as previously known.

The corner trowel as shown has a supply nipple 52 leading to receiver chamber 55. In the present case the receiving chamber is shown as being bent in a vertical plane, an expedient which can be used also in the flat trowel of Figures l to 4, in order to facilitate iinishing of bottom porti-ons of a vertical joint. The trowel blade 66 in the present case is bent into a roof or prism shape, with the front sides of the blade including a horizontal angle 67which usually should be 9() degrees; accordingly, when and as the trowel is constructed for a slightly inclined position as best shown in Figure1 5, the included angle and the plane of Figure 7 will usually be slightly more than 90 degrees, thereby maintaining the correct angle and actual use.

A series of discharge openings 68 is again formed, symmetrically with the top edge of the blade 66 and extending over a part of the length of that edge. Again a corrugated wall is used for this purpose which in this case is shown as having sections 69, 70 lying at the same angle 67 as described. The connection between4 the receiving chamber 55 and the apertures 63 is provided by wall members 71, 72, 73, extending approximately parallel with the contour of the blade which has been described.

Again a restriction in the ioW of the iinishing material, prior to its arrival at the discharge openings 68, is applied. In the present case it is occasioned mainly by the bending of the receiving chamber SS about a sharp bend 74,V an expedient which as mentioned can be used also in other types of trowels in accordance herewith.

Referring nally to Figure 8 it will be noted that a 4 trowel in accordance herewith can be constructed to t into an inside corner in approximately the same manner in which they trowel of Figure 7 fits around an outside corner. A supply nipple 82 feeds the material into a sharply bent receiving chamber 85 following the proper contour of the corner trowel 86 and discharging uniformly through a series of openings S8 which extends along and slightly below the top edge of the trowel. In similar manners other special trowels can be constructed in accordance with the present invention. In special cases it is of course possible also to modify the discharge of material from different openings 18, 68 or 88 in order to suit special materials and/ or joint constructions. Many other modifications are possible, all within the scope of my claims which follow'.

I claim:

l. A gun type trowel comprising a resilient trowel blade having an edge, a resilient wall symmetrically secured to and spaced from the trowel blade having an edge spaced a short distance below the trowel edge and adapted to form a receiving chamber and a duct with the blade, said wall having the area thereof adjacent to saidA edge corrugated to define with the blade a plurality of laterally spaced discharge nozzles of substantially uniform size, said duct being adapted to distribute heavy consistency fluid material therethrough uniformly before such flow arrives in the area of the corrugations adjacent the trowel edge, and means to feed such material through the duct and out of said nozzles.

2. A trowel as described in claim 1 wherein the blade is bent so that it substantially follows the contour of a corner.

References Cited in the ile of this patent UNITED STATES vPATENTS l Selley May 17, 1904 

